The present invention relates to a testing method and a device for the testing method according to a spectro-photometry using three wavelengths of light in which a leaking in a vessel is detected, specifically a leaking in an ampoule is detected with a dye bath technique for example blue bath method.
When a pinhole is brought about in a glass ampoule or a vial for a liquid of chemical or food, or when an ampoule is not perfectly sealed hermetically, the leakage or the bacillary pollution may be caused.
Accordingly, the dye bath technique such as blue bath method is utilized, in which when an ampoule is dipped into a dense blue dye solution, for example a solution of methylene blue or other blue dye for food, evacuated once and then brought back to the normal pressure, if the ampoule is inferior the dense dye solution is introduced into the ampoule through small holes, cracks or gaps of the glass wall. An inferior ampoule is eliminated by detecting the colour of the introduced dye solution. Conventionally such ampoule containing dye solution has been found by the visual inspection of the colour of dye solution in the ampoule. There has been a detection limit for this method. Further, it has been difficult to detect in case of coloured ampoule or coloured solution.
Therefore, for measuring the light energy transmitted through the ampoule as an optical detection method, the measuring method by two-wavelength spectro-photometry is set for in Japanese Patent Application S54-133183 (Priority U.S. Ser. No. 869554).
In the measuring method by two wavelength spectro-photometry, the light passing through a vessel and a content in the vessel is received, and divided into two fluxes with optical cables. A standard filter is provided for one flux to filter a light of wavelength uninfluenced by the characteristic wavelength as of the dye and a target filter being provided for the other flux to filter the characteristic wavelength of the dye.
The outputs from filters are detected as electric signals. These two output signals are mutually added and subtracted for obtaining the sum and the differential. In comparison with these values, the subject is judged to be good or inferior.
However, even in the measurement by the two wavelength spectrophotometry, when the vessel such as an ampoule is coloured for example in brown, the difference in colour of the individual ampoule make the absorption in the wavelength for the measurement change, therefore, even for a good ampoule is judged to be out of the judging region for a good one resulting to an inferior detection sensitivity.
Further, in case of the ampoule containing coloured liquid, the temperature change of the content itself causes the absorption to change, affecting the result of measurement.